Definition of Colloid nodular goiter:

Colloid nodular goiter is the enlargement of an otherwise normal thyroid gland.

See also: Goiter

Causes, incidence, and risk factors:

Colloid nodular goiters are also known as endemic goiters. They are usually caused by inadequate iodine in diet.

Colloid nodular goiters tend to occur in certain geographical areas with iodine-depleted soil, usually areas away from the sea coast. An area is defined as endemic for goiter if more than 10 % of children aged 6 to 12 have goiters.

Certain things in the environment may also cause thyroid enlargement.

Small- to moderate-sized goiters are relatively common in the United States. The Great Lakes, Midwest, and Intermountain regions were once known as the "goiter belt." The routine use of iodized table salt now helps prevent this deficiency.

Risk factors for colloid nodular goiters include being female, being older than 40, not getting enough iodine in your diet, living in an endemic area, and having a family history of goiters.